Shoe and shoe product



June 20, 1944.

- -T. W. ELKIN, JR., ET AL SHOE AND SHOE PRODUCT Filed July 27, 1943 FIG.;I

"PM June so,

PATENT oer-ice SHOE AND SHOE PRODUCT I Thomas W. Elkin, Jr., Lancaster, and Henry 0. Stouifer, .Manhehn 'I'ownship, Lancaster County, Pa., assignors to Armstrong Cork Company, Lancaster, 9a., a corporation of Pennsyl- Application my 2:. 1943,; Serial so. recess This invention relates to improvements in shoes and more particularly, to a shoe having one or more resilient and flexible intermediate sole elements, such as. an insole, midsole, platform sole, or the like and to an improved intermediate sole element.

Shoes generally consist of an upper, .an outsole-,. and an insole which is adjacent the foot of the wearer. In some styles and types of shoes a 'midsole or platform sole is provided between the outsole and the insole. The term .intermediate sole element" is used to include all sole elements which are disposed between the outsole and the foot of the wearer, thus including insoles, midsoles, platform soles, and the like.

Attempts have been made in recent years to' increase the comfort of shoes without undub' increasing their cost by the use of resilient intermediate sole elements of cork and rubber, felted fibrous materials, and relatively soft grades of leather to accomplish the purpose of cushioning the foot of the wearer. some of the fibrous materials which have been used have been found to be so hard and stiff as not to readily flex or absorb shocks when constructed to have sunlcient strength to wear properly. The relatively soft grades of leather are readily affected by water and are not sufliciently resilient to impart any real cushioning eflect. The rubber type cushion platform soles 'are now unobtainable be cause of governmental restrictions and many wearers object to the use of rubber adjacent the foot claiming that it has a tendency to draw" and heat." Others of the materials which have been used are relatively expensive and unduly lncreasethe cost of the final product.

A primary object of this invention is to provide an improved shoe construction in which a relatively soft cushioning eifect is obtained with the use of an inexpensive material, not affected by water, completely flexible in all dlrections,

and sumciently strong to ideallyserve for the intended purpose; which may be readily fabricated, and which will receive and hold nails orstaples in assembly or may be readily cemented 1 i P ace.

This-object is accomplished by providing a shoe constructed with one or more'intermediate. sole elements, each comprisingv a layer of cured and vulcanized siccative 'oil-re sin gel containing a reinforcing pigment and preferablycontalning cork particles.

The following typical examples, in which the parts are by weight, illustrate our invention-but s5] however, beoxidized by the so-called scrim" (cl. se-so) are not intended to limit it to the exact proportions or ingredients set forth:

Example 1 I Parts Siccative oil-resin gel- (75 parts linseed oil and 25 parts rosin) 100 Carbon black Sulf r 1.2 10 12-40 cork particles 70 Example 2 Y a I Parts Blccative oil-resin gel (75 parts soya bean oil and parts rosin) we 33 Sulfur 4 Hexamethylenetetramine accelerator l 1. Carbon black Plasticizer (light mineral oil) 10 Stearic acid 2 go Paraffin 3 12-40 cork particles--' Example 3 I Parts Siccative oil-resin gel (76 parts linseed oil a and 25 parts rosin) 10o Sulfur 4' Hexamethylenetetramine accelerator 1 Carbon black 80 of may be used. thereof or semi-drying oils or mixtures thereof may be used. Also mixtures of drying and semidrying oils may be employed. The preferred resin is rosin becauseof its cheapness and ready availability. Other'resins, such as the naturally occurring or fossil resins, may be used if desired. A reinforcin P gment like a carbon black, such a as lamp black' or channel black, is incorporated in the mass to increase the toughness and strength of the product. In order to chest vulcanlzation or curing, sulfur is preferably em-=' ployed and an accelerator, such as the hexael methylenetetramine or Examples 2 and 3 above,

is incorporated to accelerate the vulcanlzing action.

The siccative oil-resin eel is preferably produced by mechanically oxidizing the oil in the so presence of the resin by the use of a mechanical oxidizer, such as the Bedford. oxidizer. This produces a tough, elastic oil-resin gel in which" substantially all of the oil is oxidized. Such a gel may be effectively vulcanized. The oil may,

process where the oil is trickled over sheets of scrim cloth hanging in a heated chamber and oxidation and gelation of the oil occurs. The resin is then incorporated with the oil gel by the use of a heated mixer;

A substantially completely oxidized oil-resin gel produced by mechanically oxidizing a mix ture of from 70 to 80 parts linseed oil and from 30 to 20 parts rosin in a Bedford oxidizer forms. a satisfactory binder or matrix when cured and vulcanized.

The oil-resin gel as discharged from the oxidizer is preferably allowed to cool to produce a tough, relatively stiff, rubber-like mass. This is thenbroken down and the reinforcing pigment, vulcanizing agent, and.cork particles or other fillers are mixed in a heated mixer to unirormly distribute the binder over the reinforcin pigment, cork particles, and filler. The mass is then fed to a calender and a sheet of the desired thickness is is formed. During calender n a facing of cotton fabric or other suitable material may be applied to one or both faces of the sheet to increase the strength of the finished product and provide for the retention of staples, stitching and the like. The calendered sheet is preferably hung in a heated curing stove to cure and vulcanize the siccative oil. A typical curing cycle ever, it has been found necessary to first subject the mixture to a de-gassing treatment to prevent foaming and the formation of gas cells during the molding operation, unless, of course, a porous or cellular structure is desired. Thi de-gassing treatment may be accomplished in a number of ways. By one .method the ingredients are incorporated on a two-roll mill and the mixture is then placed in an oven heated to a temperature of about 300 F. The material remains in the oven for about thirty minutes. This'results in a spongy mass which is then sheeted on milling rolls. The formed sheet may be then cured and vulcanized under heat and pressure. For a sheet 0.75 inch thick, the molding may be effected at a temperature of about 285 F. to 290 F. in about twenty-five minutes. In another and preferred tie-gassing treatment, the siccative oil-resin gel, sulfur, and accelerator, if any, are mixed in a heated mixer of th Baker-Perkins or Banbury cork particles incorporated in the product.- Larger amounts of carbon black are normally employed where no cork i used. Other pigments and fillers, such as whiting, may be used, but an amount of reinforcing pigment sufficient to im- 7 part the desired toughness and strength should be incorporated in all instances.

Cork particles are preferably incorporated to impart resiliency and insulating qualities to the intermediate sole element. These properties materially enhance the comfort of the shoe.

Amounts of cork ranging from 50 to 130 parts by weight of 100 parts of oil-resin gel have been found satisfactory. The cork particles may vary in size depending upon the thickness of the sheet. Preferably cork particles of from 10 to 40 mesh United States standard screen size, 'hereln designated as 10/40, are used with the thicker intermediate sole elements, such as midsoles. and platform soles, but 12/20 cork has also been used for this purpose. such as insoles, 14/40 or 20/40 cork is generally employed.

The mixture is vulcanized in all instances to increase the toughness and elasticity of'the product. In general, those vulcanizing agents employed for vulcanizing rubber, such as' sulfur, sulfur chloride, and the like may be used. A vulcanizing accelerator, such as hexamethylenetetramine, mercaptobenzothiazole, Tuads, technically, tetramethyithiuramdisulflde, or other similar material may be used to reduce the curing and vulcanizing time.

The attached drawing illustrates a typical platform shoe of the cemented type embodying this invention, in which I Figure 1 schematically shows a sho having its forward portion cut away to disclose the construction of the sole; and

Figure 2 is an enlarged sectional view of anintermediate sole element, such as a midsole,

type to elevat the temperature of the mass to about 300 F. This treatment is continued for about thirty minutes. This not only accomplishes a de-gassing of the mixture necessary for press curing, but also reduces the'tackiness and platform sole, or insole.

,Referring to the drawing, theshoe consists of an upper 3 and a sole 4. The sole 4 includes an outsole 5, a platformsole 6, and an insole I. The platform sole 8 is provided with a facing or binding 8. The sole elements are held together and fastened to the upper 3 by cement in the type of shoe construction illustrated. Other means for In the shoe shown in Figure 1, both the insole I and the platform sole 6 are formed of our material. In some instances, it may be desirable to form only one of the intermediate sole elements of such material.

While we have illustrated and described certain preferred embodiments of our invention, it will be understood. that the same may be otherwise embodied and practiced within the scope of the following claims.

We claim:

1. In a shoe having an upper and an outer sole.

an intermediate sole element comprising a flex- With the thinner elements,

The other surface l2 of the layer l0 may ible and resilient matrixof cured and vulcanized siccative oil-resin gel having incorporated therein a reinforcing pigment to toughen and strengthen the same.

2. In a shoe having an upper and an outer sole, an intermediate sole element comprising a flexible and resilient matrix of cured and'vulcanized oxidized siccative oil gel having incorporatedsubstantially completely oxidized siccative oilresin gel having incorporated therein a reinforcing pigment to toughen and strengthen the same,

and cork particles to enhance the resilience and 4 heat insulating properties of the element.

4. In a shoe having an upper and an outer sole, an intermediate sole element comprising a flexible and resilient matrix of heat-cured siccative oil-resin gel, sulfur, and a reinforcing pigment.

5. In a shoe having an upper and an outer sole, an intermediate sole element comprising a flexible and resilient matrix of a heat-vulcanized mixture of substantially completely oxidized siccative oil and resin, sulfur and hexamethylenetetramine, said matrix having incorporated therein a carbon black reinforcing pigment to toughen and strengthen the element.

6. In a shoe having an upper and an outer sole. a midsole or platform sole comprising a flexible and resilient matrix of cured and vulcanized siccative oil-resin gel having incorporated therein a carbon black reinforcing pigment to toughen the same and cork particlesto impart resilience and heat insulating properties thereto.

'7. In a shoe having an upper and an outer sole, an insole comprising a flexible and resilient matrix of cured and vulcanized substantially completely oxidized siccative oil and resin in gel form, said matrix having incorporated therein a reinforcing pigment to toughen and strengthen the same.

8. A flexible and resilient product in sheet form suitable as an intermediate sole element comprising a matrix of cured and vulcanized siccative oilresin gel having incorporated therein a carbon black reinforcing pigment to toughen and strengthen the matrix and cork particles to increase the resilience of the product and enhance f its insulating value. YY

9. A resilient and elastic product as defined in claim 7 having a reinforcing layer of fabric on at least one surface of said sheet.

10. An intermediate sole element comprising a matrix of cured and vulcanized substantially completely oxidized siccativeoil and resin in. gel

form having incorporated therein a reinforcing pigment to toughen and strengthen the matrix.

11. An intermediate sole element comprising a flexible and-resilient matrix of cured and vul- 

